Fault codeP0357

SEVERE

Ignition Coil G Primary/Secondary Circuit Malfunction

What this code means

Ignition Coil G Primary/Secondary Circuit Malfunction.

P0357 is a generic code: it means the same thing on every make. P0357 belongs to family P03xx — Ignition and misfire. Its page explains how to read a code and groups all its codes by part.

Type of fault

The control unit has detected an electrical anomaly on this circuit without saying exactly which. Diagnosis starts with a visual check of the wiring and connector, then measuring the component — resistance, supply, ground — with a multimeter.

Ignition coil

The ignition coil turns the 12 volts of the battery into the tens of thousands of volts needed to make a spark at the plug. On most modern engines each cylinder has its own coil, sitting directly on the plug; the control unit switches each one and monitors its primary circuit.

What you notice

The cylinder concerned misfires: shaking, loss of power, the warning light possibly flashing.

How to check it

Swap the coil with that of a neighbouring cylinder: if the fault moves with it, the coil is at fault. Also check the connector and wiring; cracks on the coil body or traces of moisture in the plug well are classic causes.

What to do

Have it checked promptly. A misfire sends unburnt fuel into the exhaust and destroys the catalytic converter within a few dozen kilometres. If the light is flashing, stop driving.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
3Ignition and misfire
57P0357